Headphones don’t work.
Plug in headphones after starting computer but before starting Zoom. When plugging in, it will ask you did you insert headset or headphones. Choose headset to use the mic. If this doesn’t work: In the "Type here to search" enter "Sound settings". Under "master volume" and "trouble shoot" there is a button labeled "Manage sound devices", click on this. Under "Output devices" check to make sure that "headphones" aren't listed under "Disabled." If they are, click on them and select "Enable." This should allow you to toggle between headphones and the device's speakers when you click on the speaker icon to the left of date and time.